Hammer mill hammers with replaceable tip



I United States Patent [72] Inventor Robert P.Anenault References Cited Joliette, Quebec, Cinldl UNITED STATES PATENTS [3;] 91 13. 968 3,207,448 9/1965 Miller 241/197 E45} P afented 8: 1970 Primary Examiner-Robert C. Riordon [73] Assignee Abex Corporation ASSiSlantExaminer-Donald Kelly New York, New York I Att0rney--Kmzer, Born and ZIckert a corporation of Delaware ABSTRACT: A two-piece hammer assembly for use in a hammer mill comprises a replaceable tip supported at the bottom of a shank, preferably by a tongue-and-groove interfit [S4] HAMME MILL HAMMERS WITH REPLACEABLE enabling the parts to he slid together in the course of asllP sembly. The two are secured by a rubber block which also 7 Claim 7 8 helps maintain good bearing contact between the two; in fact, [52} U.S.Cl. 241/197 the rubber lock presents a holding force of sufficient mag- [511 In H 3021; 13/28 nitude as to require forced leverage in completing the as- [50] Field ofSearch 241/195, sembly, n he p r r o constructed as to enable such leverage to be readily achieved by a prise.

PATENTED DEC 8 i976 SHEET 10F 3 lNVE NTOR ROBERT P. ARSENAU LT FDMMZM ATTORNEYS PATENTED nu: 8 I970 SHEET 2 OF 3 INVENTOR ROBERT P. ARSENAULT ATTORNEYS PATENTED [15s a rain sum 3 or 3 FIG? INVENTOR ROBERT P. ARSENAULT BY k 9 DM,MZW

ATTORNEYS HAMMER MILL IIAMMERS WITH REPLACEABLE TIP The present invention relates to a two-piece renewable hammer of the kind used in hammer mills where rocks or other earthy material are to be crushed or comminuted. A two-piece assembly of this kind should display good bearing contact, a tight fit, that is, between the tip and the shank, and one of the primary objects of the present invention is to enable this desirable end to be achieved, while at the same time enabling the parts to be assembled or disassembled in a minimum time so that the time in which the operation of the mill is interrupted will be a minimum.

A related object of the present invention is to achieve the foregoing by means of a lock in the form of a rubber block representing a highly effective but nonetheless relatively inexpensive approach. I

Specifically, it is an object of the present invention to interpose a rubber lock between a tip member and a shank member of a two-piece hammer assembly, but under circumstances where the one member presents a large bearing shoulder slidably interfitting a groove in the other member, final alignment being achieved by a pn's'e which forces a protuberance on one member into seating engagement with the rubber block, manifesting the efficiency of the rubber lock.

Other and further objects of the present invention will be apparent from the following description and claims and are illustrated in the accompanying drawings which, by way of illustration, show a preferred embodiment of the present invention and the principle thereof and what is now considered to be the best mode contemplated for applying that principle. Other embodiments of the invention embodying the same or equivalent principles may be used and structural changes may be made as desired by those skilled in the art without departing from the present invention.

In the drawings:

FIG. 1 is a side elevation of a hammer constructed in accordance with the presentinvention;

FIG. 2 is an elevation on the line 2-2 of FIG. 1, but with the assembly partly broken away;

FIG. 3 is an end elevation on the line 3-3 of FIG. 1 but with the hammer tip removed to expose the bottom of the shank;

FIG. 4 is a bottom plan view of the assembly substantially on the line 4-4 of FIG. 1.

' FIGS. 5 and 6 are elevations of the rubber lock, but on an enlarged scale compared .to FIGS. 1 and 2; and

FIG. 7 is an exploded perspective view of the hammer parts.

The hammer 10 of the present invention, FIGS. 1 and 2, includes a hammer shank 1l,a hammer tip 12 and a rubber lock 13. The hammer shank at its lower end supports the tip, and at the upper end is provided with an aperture 15 serving to mount the assembly on the shaft of the hammer mill, not shown. Wear is negligible'on the shank 11, but the operating face of the hammer tip is subjected to constant attrition during the course of operation. In this connection it will be noted that the hammer tip is of symmetrical geometry, which is to say that either the face 12F or the face 12R of the hammer tip may perform the act of crushing or comminution when the hammer is installed in a mill, depending upon the direction of rotation.

The present invention is concerned primarily with increasing the efficiency of hammer operation and tip replacement so that the time the mill is shut down will be at a minimum during such replacement; this efficiency aspect centers on the rubber lock 13.

Basically, the tip is united to the shank by a tongue-andgroove interfit affording ample bearing surfaces between the tip and shank. Thus, the lower end of the shank is characterized by a head which supports the tip, somewhat T-shaped as will be evident in FIG. 1, presenting parallel, elongated grooves 17 and I8 on opposite sides, FIG. 1, and these grooves are complemental to a corresponding pair of tongues 19 and 20 on the tip 12 which project inwardly toward one another.

At the same time, the tip is formed with a large T-shaped recess 22 in the medial portion thereof, complemental to the mounting head of the shank. This recess opens at both ends of the tip, FIG. 2, and opens at the top wall of the tip, FIG. 1, throughout the length of the hammer tip.

v The recess 22 is undercut at 24 and 25 not only to afford the tongues but also to afford elongated grooves within the tip. Outwardly projecting tongues 27 and 28, at the bottom of the shank head, fit in the grooves'24 and 25.

It will be recognized that in fitting the hammer tip member to the lower end of the shank member, the tongues of one member are aligned with the grooves of the other, and the one is slipped onto the other.

The rubber lock 13 is used to secure the tip on the shank against displacement and so that good bearing contact will be maintained between the upper surfaces 27A and 28A of the hammer shank tongues and the opposed or lower surfaces 19A and 20A of the hammer tip tongues. The rubber block 13 at the same time prevents lateral or longitudinal movement of the tip relative to the shank. The rubber block presents an insert in the form of a steel pin 13?, FIGS. 2 and 5, vulcanized or otherwise bonded thereto.

When properly positioned, asexplained in detail below, the media] portion of the rubber block which presents the pin 13? projects into the recess 22 of the hammer tip, in alignment with a through-slot 30, FIG. 3, at the bottom of the hammer shank.

The rubber lock, FIGS. 5 ad 6, is generally of rectangular contour, being defined in part by a flat bottom wall 138 rounded lower edges 13C, flat side walls 13D, a convex top wall 13R, and a rounded medial protuberance I3T where the pin 13? is located. The endwalls are flat and parallel at 13F, and then are tapered inwardly at 13E.

The hammer tip, at the interior medial area of the recess 22, is fonned with a rectangular slot 35, FIGS. 2 and 4, afi'ording a mounting and retaining socket for the rubber lock. The areas of the seat may be of somewhat less dimension than the block, so that the rubber block will be slightly compressed when installed in the socket, with the convex wall 13R uppermost, although such compression is not essential. The curved lower edges 13C of the block, and the tapers 13E facilitate positioning of the block 13 in the socket.

The lower end of the hammer shank 11, FIG. 2, at its medial area, is formed with a convexprotuberance 36 which projects part way into the shank slot 30, and the protuberance 36 is formed with a slight concavity 37 serving as a seat for the medial portion 13T of the convex upper wall of the rubber block 13 presenting the pin 13F.

To assemble the hammer tip on the hammer shank, the rubber block 13 is located in its socket as shown in FIG. 2. Let it be assumed, FIG. 2, that the left hand end of the tip 12 as viewed in FIG. 2 is to be slipped onto the right hand end of the shank head. The hammer tip is' then slipped by hand onto one end of the T-shaped head of the shank until the rubber block encounters the protuberance 36 of the hammer shank which projects into the slot or guideway 30. When this position is attained, a crowbar or other prise is then inserted into the proper one of two openings 40 formed in the lower wall of the hammer tip, on opposite sides of the socket 35, and which open into the hammer tip recess 22. This will be the right hand opening 40, FIG. 2.

The prise is manipulated until the working end thereof is disposed in a related opposed socket 41 formed in the wall of the hammer shank which bounds the upper side of the through-slot 30. The prise is then capable of being used as a second class lever, the bounding wall of the slot 41 serving as the fulcrum (fixed) point, and the hammer tip is then pried or forced sideways (leftwards, FIG. 2) along the length of the lower end of the hammer shank until the steel pin ISP of the rubber block is aligned with and snaps into the recess 37. During this movement, the prise at its intermediate portion will be acting on the edge 40A of the opening 40. Note that the protuberance 36 at 36R and the rubber block at 13R have rounded or tapered sides to facilitate forced movement therebetween when the rubber block is being compressed by the protuberance 36.

In this connection, it will be observed that the axis of the opening 40 and the axis of the fulcrum socket M are slightly offset in order to obtain the best mechanical advantage. It may furthermore be pointed out in connection with the symmetry mentioned above that the two sets of openings 40-4l are themselves symmetrical and offset in identical fashion so that forced assembly may be achieved by working at either end of the hammer tip as will be apparent in FIG. 2. It will also be appreciated that the rubber block itself is under a great deal of compression in the installed state represented by FIG. 2.

Once the parts are locked together as shown in FlG. 2, the rubber lock 13 applies a great deal of downward force on the hammer tip, maintaining a positive bearing contact between the surfaces 27A and 28A, FIG. 1, and consequently an efficient, rigid relationship between the hammer tip and the shank is maintained, contributing to the effectiveness of the hammer in operation, which is to say that there is very little, if any, tendency toward a loose fit by which centrifugal force is dissipated or lessened substantially in the course of rotation of the hammer in the mill.

When the tip is to be removed for replacement, the prise is again inserted through the right-hand one of the openings 40, FIG. 2, but this time the end of the prise is to be engaged with the right-hand end of the shank head, preferably disposed on a tapered surface 42 provided at the remote end of the shank for this very purpose. Then, using the slot or tapered wall 42 as the fulcrum this time, sufficient leverage is applied to withdraw the tip from the shank in a right-hand direction as viewed in FIG. 2. At this time, the prise at its intermediate section will be bearing on the edge 40B of the opening 40.

Advantageously an opening 45 is formed in the bottom wall of the hammer tip to communicate with the seat recess 35 to facilitate removal of the rubber block when desired.

It will be seen from the foregoing that a highly efficient arrangement has been realized for locating and securing a replaceable tip on a hammer shank. Fundamentally, the two slide together along surfaces which are bearing areas, enabling the shank to absorb a great deal of the impact encountered by the tip during operation. This in itself conserves the tip, and good bearing contact is achieved by the rubber lock, manifest in the fact that the protuberance 36 can only be seated on the rubber block by means of leverage applied by a prise, forcing the protuberance 36 into seated and aligned relationship with the rubber lock. It will therefore be appreciated that many of the surfaces and parts herein identified as being on one member or part may in fact be reversed to be presented by the others. This is so with respect to the tongue-and-groove interfit; and as a further example, the seat between the block 13 and protuberance 36 could be reversed.

Hence, while a preferred embodiment of the invention has been described and illustrated, it is to be understood that this is capable of variation and modification.

I claim:

1. In a two-piece hammer having a shank member and a replaceable tip member with interfrtting parts for locating the tip on the shank, a replaceable hammer tip formed with an enlarged recess of predetermined contour for slidably receiving a portion of the hammer shank shaped complemental thereto during assembly and by which the one member supports the other when assembled, said hammer tip being formed with a cavity serving as a socket for a resilient block having a portion projecting into said recess at an intermediate portion thereof and engageable in a tight seated fit with a protuberance on the hammer shank when the members are fully assembled, said protuberance abutting a side of the projecting portion of the resilient block during slidable assembly, and said hammer tip having an opening in one wall thereof adjacent said socket and which communicates with said recess enabling a prise to be entered in the opening and engaged with an opposed surface of the shank to serve as a lever for forcing said protuberance over said side of the resilient block and into seated engagement with the resilient block.

2. A hammer tip according to claim 1 in which there are two openings for the prise, one on either side of said socket.

3. A hammer tip according to claim 1 having a pair of elongated tongues over-hangingI said recess to slidably fit core amrner shank, said recess being responding grooves in generally T-shaped and opening at opposite ends of the tip.

4. In a two-piece hammer characterized by a hammer shank having an end wall with a protuberance thereon engageable with a resilient block in a hammer tip to maintain the tip against dislodgrnent on the shank, a hammer tip having a bottom wall and a large recess opening at the top of the tip, said hammer tip having a projecting tongue overhanging said recess to interfit with a complemental groove in the hammer shank upon relative sliding movement of the tongue into the groove, a socket located in the bottom wall of the tip and communicating with said recess and serving to house a resilient block projecting part way into said recess, and an opening in the bottom wall of the tip adjacent one side of said socket and communicating with said recess so that a prise entered in said opening and disposed in engagement with the hammer shank may be fulcrummed about a solid portion defining said opening to force the protuberance of the hammer shank into seated engagement with the resilient block.

5. A hammer tip according to claim 4 in which there are two openings for the prise, one on either side of said socket.

6. A hammer tip according to claim '5 in which the socket is located medially of the recess in the tip, said recess extending through the tip to open at opposite ends thereof, the tip having a second tongue identical to the first-named tongue so that there are two such tongues extending the length of the recess at opposite sides thereof and each fittable in a corresponding groove in the hammer shank.

7. In a two-piece hammer having a shank member and a replaceable tip member with interfitting parts for locating the tip on the shank and comprising, a replaceable hammer tip formed with an enlarged recess of predetermined contour for slidably receiving a portion of the hammer shank shaped complemental thereto and by which the shank supports the tip, said hammer tip being formed with a cavity serving as a socket in which is mounted a resilient block having a portion projecting into said recess and engaged in a tight seated fit with a medially located protuberance on the hammer shank, said recess in the tip serving to receive a tongue on the shank presenting a bearing surface in contact with an opposing sur-- face of the tip bounding said recess, said shank having a slot therein aligned with said portion of the block which projects into said recess and said protuberance projecting into said slot whereby the tip may be slid onto the shank until the block meets the protuberance, and an opening in the bottom wall of the tip adjacent said socket and communicating with said recess enabling a prise to be inserted therethrough with the inner end thereof engaged with the shank, using the prise as a lever to produce relative movement between the shank and tip forcing the block and protuberance into seating engagement with one another. 

